Another source is taken from the water cooler. Look at how many bacteria colonies have formed. @_@. I think the water cooler is rusting and favor growth of many bacteria. Do you dare to drink water from this water cooler? Surprisingly, there is another source taken from the dustbin and it shows almost no bacteria colonies....herm..

This experiment tells you how dangerous UV light can be. The upper side is exposed to UV ray. You can observed no lawn of bacteria at all, not even a single colony. All of the bacteria has been killed by the UV ray. Sayonara. Imagine if it is exposed to our skin...Eye cataract, skin cancer and much more..